It's not really possible to make an ID from these photos. However, no British spiders are actually dangerous and there are totally harmless species that are often mistaken for false widows.

But let's take the worst case scenario & assume that it might possibly be a false widow (presumably the reason you posted in the first place, I'm not saying that it is a false widow, just "if it is")...there are a few things to bear in mind from your photo. The spider is high up off the floor, well away from where your little boy will be. It's up there to be away from threats such as people, pets & predators. If it is established in a web up there, it isn't going to want to come down to floor level if it can help it & is unlikely to move far from its hiding place.

I'd watch it for a few days, see where & how far it moves, best to see it after dusk as it will likely hide away during the day. If it sticks to the same small area, high up & out of reach, I don't think there's anything to worry about. Females are territorial and for the most part solitary, they don't live in colonies or nests.

If you have any fears or doubts (it is perfectly understandable to want such a spider out of the house altogether), then remove it. However, they can move at quite speed when threatened (running away that is, they aren't aggressive & don't charge at/chase people) & she may not be easy to catch. Trying to do so is more likely to bring her into contact with one of the family. Also, trying & failing to catch her might possibly displace her and leave her roaming around looking for a new home?

All in all, *if* she is a false widow, living in a difficult to get to, out of the way spot - it makes as much sense to leave her there as it does to disturb her?

Better photos would be good for an ID...but I appreciate this may not be easy based on my own attempts to photograph a false widow that lives in my front room.